Trail following in army ants (Hymenoptera, Formicidae)

Abstract

Army ants form impressive columns that rely on the following of trail pheromones. We could study trail following in three army ant species and locate the glandular source of the respective active pheromones. Eciton burchelli (Ecitoninae) produces very long lasting trails from a specialized glandular epithelium associated with the 7th abdominal sternite, while in Dorylus molestus (Dorylini) short-lasting trails are elaborated from the venom gland. In Aenictus sp. near laeviceps (Aenictini), the secretion of the well developed postpygidial glands forms the long-lasting trail pheromone, which in this species could be chemically identified as a two-component system with methyl nicotinate (1% of gland secretion) initiating the ants to follow a trail, and methyl anthranilate (99%) causing the real trail following.